Merge branch 'master' into plugin-message-event

# Conflicts:
#	proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java
#	proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

README.md

@@ -44,5 +44,4 @@ is not currently suitable for production usage. For development and testing
 purposes, however, Velocity is fully-fledged and ready to go.
 
 Velocity supports Minecraft 1.8-1.13.1, and has full support for Paper and Sponge.
-Forge support is currently not implemented, but Velocity will work with Forge's
-vanilla fallback mode.
+Forge is fully supported but mod compatibility may vary.

api/src/main/java/com/velocitypowered/api/event/connection/PostLoginEvent.java

@@ -0,0 +1,28 @@
+package com.velocitypowered.api.event.connection;
+
+import com.google.common.base.Preconditions;
+import com.velocitypowered.api.proxy.Player;
+
+/**
+ * This event is fired once the player has been successfully authenticated and
+ * fully initialized and player will be connected to server after this event
+ */
+public class PostLoginEvent {
+
+    private final Player player;
+
+    public PostLoginEvent(Player player) {
+        this.player = Preconditions.checkNotNull(player, "player");
+    }
+
+    public Player getPlayer() {
+        return player;
+    }
+
+    @Override
+    public String toString() {
+        return "PostLoginEvent{"
+                + "player=" + player
+                + '}';
+    }
+}

api/src/main/java/com/velocitypowered/api/event/connection/PreLoginEvent.java

@@ -3,8 +3,10 @@ package com.velocitypowered.api.event.connection;
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.event.ResultedEvent;
 import com.velocitypowered.api.proxy.InboundConnection;
+import java.util.Optional;
 
 import net.kyori.text.Component;
+import net.kyori.text.serializer.ComponentSerializers;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
@@ -52,44 +54,59 @@ public class PreLoginEvent implements ResultedEvent<PreLoginEvent.PreLoginCompon
     }
 
     /**
-     * Represents an "allowed/allowed with online mode/denied" result with a reason allowed for denial.
+     * Represents an "allowed/allowed with forced online\offline mode/denied" result with a reason allowed for denial.
      */
-    public static class PreLoginComponentResult extends ResultedEvent.ComponentResult {
-        private static final PreLoginComponentResult ALLOWED = new PreLoginComponentResult((Component) null);
-        private static final PreLoginComponentResult FORCE_ONLINEMODE = new PreLoginComponentResult(true);
+    public static class PreLoginComponentResult implements ResultedEvent.Result {
 
-        private final boolean onlineMode;
+        private static final PreLoginComponentResult ALLOWED = new PreLoginComponentResult(Result.ALLOWED, null);
+        private static final PreLoginComponentResult FORCE_ONLINEMODE = new PreLoginComponentResult(Result.FORCE_ONLINE, null);
+        private static final PreLoginComponentResult FORCE_OFFLINEMODE = new PreLoginComponentResult(Result.FORCE_OFFLINE, null);
 
-        /**
-         * Allows online mode to be enabled for the player connection, if Velocity is running in offline mode.
-         * @param allowedOnlineMode if true, online mode will be used for the connection
-         */
-        private PreLoginComponentResult(boolean allowedOnlineMode) {
-            super(true, null);
-            this.onlineMode = allowedOnlineMode;
+        private final Result result;
+        private final Optional<Component> reason;
+
+        private PreLoginComponentResult(Result result, @Nullable Component reason) {
+            this.result = result;
+            this.reason = Optional.ofNullable(reason);
         }
 
-        private PreLoginComponentResult(@Nullable Component reason) {
-            super(reason == null, reason);
-            // Don't care about this
-            this.onlineMode = false;
+        @Override
+        public boolean isAllowed() {
+            return result != Result.DISALLOWED;
+        }
+
+        public Optional<Component> getReason() {
+            return reason;
         }
 
         public boolean isOnlineModeAllowed() {
-            return this.onlineMode;
+            return result == Result.FORCE_ONLINE;
+        }
+
+        public boolean isForceOfflineMode() {
+            return result == Result.FORCE_OFFLINE;
         }
 
         @Override
         public String toString() {
+            if (isForceOfflineMode()) {
+                return "allowed with force offline mode";
+            }
             if (isOnlineModeAllowed()) {
                 return "allowed with online mode";
             }
-            
-            return super.toString();
+            if (isAllowed()) {
+                return "allowed";
+            }
+            if (reason.isPresent()) {
+                return "denied: " + ComponentSerializers.PLAIN.serialize(reason.get());
+            }
+            return "denied";
         }
 
         /**
-         * Returns a result indicating the connection will be allowed through the proxy.
+         * Returns a result indicating the connection will be allowed through
+         * the proxy.
          * @return the allowed result
          */
         public static PreLoginComponentResult allowed() {
@@ -97,23 +114,41 @@ public class PreLoginEvent implements ResultedEvent<PreLoginEvent.PreLoginCompon
         }
 
         /**
-         * Returns a result indicating the connection will be allowed through the proxy, but the connection will be
-         * forced to use online mode provided that the proxy is in offline mode. This acts similarly to {@link #allowed()}
-         * on an online-mode proxy.
+         * Returns a result indicating the connection will be allowed through
+         * the proxy, but the connection will be forced to use online mode
+         * provided that the proxy is in offline mode. This acts similarly to
+         * {@link #allowed()} on an online-mode proxy.
          * @return the result
          */
         public static PreLoginComponentResult forceOnlineMode() {
             return FORCE_ONLINEMODE;
         }
 
+        /**
+         * Returns a result indicating the connection will be allowed through
+         * the proxy, but the connection will be forced to use offline mode even
+         * when proxy running in online mode
+         * @return the result
+         */
+        public static PreLoginComponentResult forceOfflineMode() {
+            return FORCE_OFFLINEMODE;
+        }
+
         /**
          * Denies the login with the specified reason.
          * @param reason the reason for disallowing the connection
          * @return a new result
          */
-        public static PreLoginComponentResult denied(@NonNull Component reason) {
+        public static PreLoginComponentResult denied(Component reason) {
             Preconditions.checkNotNull(reason, "reason");
-            return new PreLoginComponentResult(reason);
+            return new PreLoginComponentResult(Result.DISALLOWED, reason);
+        }
+
+        private enum Result {
+            ALLOWED,
+            FORCE_ONLINE,
+            FORCE_OFFLINE,
+            DISALLOWED
         }
     }
 }

api/src/main/java/com/velocitypowered/api/event/player/KickedFromServerEvent.java

@@ -0,0 +1,118 @@
+package com.velocitypowered.api.event.player;
+
+import com.google.common.base.Preconditions;
+import com.velocitypowered.api.event.ResultedEvent;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.server.ServerInfo;
+import net.kyori.text.Component;
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+/**
+ * Fired when a player is kicked from a server. You may either allow Velocity to kick the player (with an optional reason
+ * override) or redirect the player to a separate server.
+ */
+public class KickedFromServerEvent implements ResultedEvent<KickedFromServerEvent.ServerKickResult> {
+    private final Player player;
+    private final ServerInfo server;
+    private final Component originalReason;
+    private final boolean duringLogin;
+    private ServerKickResult result;
+
+    public KickedFromServerEvent(Player player, ServerInfo server, Component originalReason, boolean duringLogin, Component fancyReason) {
+        this.player = Preconditions.checkNotNull(player, "player");
+        this.server = Preconditions.checkNotNull(server, "server");
+        this.originalReason = Preconditions.checkNotNull(originalReason, "originalReason");
+        this.duringLogin = duringLogin;
+        this.result = new DisconnectPlayer(fancyReason);
+    }
+
+    @Override
+    public ServerKickResult getResult() {
+        return result;
+    }
+
+    @Override
+    public void setResult(@NonNull ServerKickResult result) {
+        this.result = Preconditions.checkNotNull(result, "result");
+    }
+
+    public Player getPlayer() {
+        return player;
+    }
+
+    public ServerInfo getServer() {
+        return server;
+    }
+
+    public Component getOriginalReason() {
+        return originalReason;
+    }
+
+    public boolean kickedDuringLogin() {
+        return duringLogin;
+    }
+
+    /**
+     * Represents the base interface for {@link KickedFromServerEvent} results.
+     */
+    public interface ServerKickResult extends ResultedEvent.Result {}
+
+    /**
+     * Tells the proxy to disconnect the player with the specified reason.
+     */
+    public static class DisconnectPlayer implements ServerKickResult {
+        private final Component component;
+
+        private DisconnectPlayer(Component component) {
+            this.component = Preconditions.checkNotNull(component, "component");
+        }
+
+        @Override
+        public boolean isAllowed() {
+            return true;
+        }
+
+        public Component getReason() {
+            return component;
+        }
+
+        /**
+         * Creates a new {@link DisconnectPlayer} with the specified reason.
+         * @param reason the reason to use when disconnecting the player
+         * @return the disconnect result
+         */
+        public static DisconnectPlayer create(Component reason) {
+            return new DisconnectPlayer(reason);
+        }
+    }
+
+    /**
+     * Tells the proxy to redirect the player to another server. No messages will be sent from the proxy
+     * when this result is used.
+     */
+    public static class RedirectPlayer implements ServerKickResult {
+        private final ServerInfo server;
+
+        private RedirectPlayer(ServerInfo server) {
+            this.server = Preconditions.checkNotNull(server, "server");
+        }
+
+        @Override
+        public boolean isAllowed() {
+            return false;
+        }
+
+        public ServerInfo getServer() {
+            return server;
+        }
+
+        /**
+         * Creates a new redirect result to forward the player to the specified {@code server}.
+         * @param server the server to send the player to
+         * @return the redirect result
+         */
+        public static RedirectPlayer create(ServerInfo server) {
+            return new RedirectPlayer(server);
+        }
+    }
+}

api/src/main/java/com/velocitypowered/api/event/player/ServerPreConnectEvent.java

@@ -14,11 +14,13 @@ import java.util.Optional;
  */
 public class ServerPreConnectEvent implements ResultedEvent<ServerPreConnectEvent.ServerResult> {
     private final Player player;
+    private final ServerInfo originalServer;
     private ServerResult result;
 
-    public ServerPreConnectEvent(Player player, ServerResult result) {
+    public ServerPreConnectEvent(Player player, ServerInfo originalServer) {
         this.player = Preconditions.checkNotNull(player, "player");
-        this.result = Preconditions.checkNotNull(result, "result");
+        this.originalServer = Preconditions.checkNotNull(originalServer, "originalServer");
+        this.result = ServerResult.allowed(originalServer);
     }
 
     public Player getPlayer() {
@@ -35,10 +37,15 @@ public class ServerPreConnectEvent implements ResultedEvent<ServerPreConnectEven
         this.result = Preconditions.checkNotNull(result, "result");
     }
 
+    public ServerInfo getOriginalServer() {
+        return originalServer;
+    }
+
     @Override
     public String toString() {
         return "ServerPreConnectEvent{" +
                 "player=" + player +
+                ", originalServer=" + originalServer +
                 ", result=" + result +
                 '}';
     }
@@ -50,11 +57,11 @@ public class ServerPreConnectEvent implements ResultedEvent<ServerPreConnectEven
         private static final ServerResult DENIED = new ServerResult(false, null);
 
         private final boolean allowed;
-        private final ServerInfo info;
+        private final ServerInfo server;
 
-        private ServerResult(boolean allowed, @Nullable ServerInfo info) {
+        private ServerResult(boolean allowed, @Nullable ServerInfo server) {
             this.allowed = allowed;
-            this.info = info;
+            this.server = server;
         }
 
         @Override
@@ -62,8 +69,8 @@ public class ServerPreConnectEvent implements ResultedEvent<ServerPreConnectEven
             return allowed;
         }
 
-        public Optional<ServerInfo> getInfo() {
-            return Optional.ofNullable(info);
+        public Optional<ServerInfo> getServer() {
+            return Optional.ofNullable(server);
         }
 
         @Override
@@ -71,7 +78,7 @@ public class ServerPreConnectEvent implements ResultedEvent<ServerPreConnectEven
             if (!allowed) {
                 return "denied";
             }
-            return "allowed: connect to " + info.getName();
+            return "allowed: connect to " + server.getName();
         }
 
         public static ServerResult denied() {

api/src/main/java/com/velocitypowered/api/proxy/server/ServerPing.java

@@ -4,7 +4,6 @@ import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.util.Favicon;
 import net.kyori.text.Component;
-import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.*;
@@ -17,12 +16,18 @@ public class ServerPing {
     private final Players players;
     private final Component description;
     private final @Nullable Favicon favicon;
+    private final Modinfo modinfo;
 
     public ServerPing(Version version, @Nullable Players players, Component description, @Nullable Favicon favicon) {
+        this(version, players, description, favicon, Modinfo.DEFAULT);
+    }
+
+    public ServerPing(Version version, @Nullable Players players, Component description, @Nullable Favicon favicon, @Nullable Modinfo modinfo) {
         this.version = Preconditions.checkNotNull(version, "version");
         this.players = players;
         this.description = Preconditions.checkNotNull(description, "description");
         this.favicon = favicon;
+        this.modinfo = modinfo;
     }
 
     public Version getVersion() {
@@ -41,6 +46,10 @@ public class ServerPing {
         return Optional.ofNullable(favicon);
     }
 
+    public Optional<Modinfo> getModinfo() {
+        return Optional.ofNullable(modinfo);
+    }
+
     @Override
     public String toString() {
         return "ServerPing{" +
@@ -54,11 +63,19 @@ public class ServerPing {
     public Builder asBuilder() {
         Builder builder = new Builder();
         builder.version = version;
-        builder.onlinePlayers = players.online;
-        builder.maximumPlayers = players.max;
-        builder.samplePlayers.addAll(players.sample);
+        if (players != null) {
+            builder.onlinePlayers = players.online;
+            builder.maximumPlayers = players.max;
+            builder.samplePlayers.addAll(players.sample);
+        } else {
+            builder.nullOutPlayers = true;
+        }
         builder.description = description;
         builder.favicon = favicon;
+        builder.nullOutModinfo = modinfo == null;
+        if (modinfo != null) {
+            builder.mods.addAll(modinfo.modList);
+        }
         return builder;
     }
 
@@ -74,9 +91,11 @@ public class ServerPing {
         private int onlinePlayers;
         private int maximumPlayers;
         private final List<SamplePlayer> samplePlayers = new ArrayList<>();
+        private final List<Mod> mods = new ArrayList<>();
         private Component description;
         private Favicon favicon;
         private boolean nullOutPlayers;
+        private boolean nullOutModinfo;
 
         private Builder() {
 
@@ -102,11 +121,26 @@ public class ServerPing {
             return this;
         }
 
+        public Builder mods(Mod... mods) {
+            this.mods.addAll(Arrays.asList(mods));
+            return this;
+        }
+
+        public Builder clearMods() {
+            this.mods.clear();
+            return this;
+        }
+
         public Builder clearSamplePlayers() {
             this.samplePlayers.clear();
             return this;
         }
 
+        public Builder notModCompatible() {
+            this.nullOutModinfo = true;
+            return this;
+        }
+
         public Builder nullPlayers() {
             this.nullOutPlayers = true;
             return this;
@@ -123,7 +157,8 @@ public class ServerPing {
         }
 
         public ServerPing build() {
-            return new ServerPing(version, nullOutPlayers ? null : new Players(onlinePlayers, maximumPlayers, samplePlayers), description, favicon);
+            return new ServerPing(version, nullOutPlayers ? null : new Players(onlinePlayers, maximumPlayers, samplePlayers), description, favicon,
+                    nullOutModinfo ? null : new Modinfo(mods));
         }
 
         public Version getVersion() {
@@ -150,6 +185,10 @@ public class ServerPing {
             return favicon;
         }
 
+        public List<Mod> getMods() {
+            return mods;
+        }
+
         @Override
         public String toString() {
             return "Builder{" +
@@ -157,8 +196,11 @@ public class ServerPing {
                     ", onlinePlayers=" + onlinePlayers +
                     ", maximumPlayers=" + maximumPlayers +
                     ", samplePlayers=" + samplePlayers +
+                    ", mods=" + mods +
                     ", description=" + description +
                     ", favicon=" + favicon +
+                    ", nullOutPlayers=" + nullOutPlayers +
+                    ", nullOutModinfo=" + nullOutModinfo +
                     '}';
         }
     }
@@ -247,4 +289,25 @@ public class ServerPing {
                     '}';
         }
     }
+
+    public static class Modinfo {
+        public static final Modinfo DEFAULT = new Modinfo(ImmutableList.of());
+
+        private final String type = "FML";
+        private final List<Mod> modList;
+
+        public Modinfo(List<Mod> modList) {
+            this.modList = ImmutableList.copyOf(modList);
+        }
+    }
+
+    public static class Mod {
+        private final String id;
+        private final String version;
+
+        public Mod(String id, String version) {
+            this.id = Preconditions.checkNotNull(id, "id");
+            this.version = Preconditions.checkNotNull(version, "version");
+        }
+    }
 }

api/src/main/java/com/velocitypowered/api/util/GameProfile.java

@@ -57,7 +57,7 @@ public final class GameProfile {
                 '}';
     }
 
-    public final class Property {
+    public final static class Property {
         private final String name;
         private final String value;
         private final String signature;

build.gradle

@@ -13,8 +13,8 @@ allprojects {
         // dependency versions
         junitVersion = '5.3.0-M1'
         slf4jVersion = '1.7.25'
-        log4jVersion = '2.11.0'
-        nettyVersion = '4.1.28.Final'
+        log4jVersion = '2.11.1'
+        nettyVersion = '4.1.29.Final'
         guavaVersion = '25.1-jre'
 
         getCurrentBranchName = {
@@ -27,6 +27,17 @@ allprojects {
                 return os.toString().trim()
             }
         }
+
+        getCurrentShortRevision = {
+            new ByteArrayOutputStream().withStream { os ->
+                exec {
+                    executable = "git"
+                    args = ["rev-parse", "HEAD"]
+                    standardOutput = os
+                }
+                return os.toString().trim().substring(0, 8)
+            }
+        }
     }
 
     repositories {

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10-all.zip

proxy/build.gradle

@@ -14,8 +14,11 @@ compileTestJava {
 
 jar {
     manifest {
+        def buildNumber = System.getenv("BUILD_NUMBER") ?: "unknown"
+        def version = "${project.version} (git-${project.ext.getCurrentShortRevision()}, build ${buildNumber})"
+
         attributes 'Main-Class': 'com.velocitypowered.proxy.Velocity'
-        attributes 'Implementation-Version': project.version
+        attributes 'Implementation-Version': version
     }
 }
 

proxy/src/main/java/com/velocitypowered/proxy/Velocity.java

@@ -19,7 +19,7 @@ public class Velocity {
 
     public static void main(String... args) {
         startTime = System.currentTimeMillis();
-        logger.info("Booting up Velocity...");
+        logger.info("Booting up Velocity {}...", Velocity.class.getPackage().getImplementationVersion());
 
         VelocityServer server = new VelocityServer();
         server.start();

proxy/src/main/java/com/velocitypowered/proxy/command/VelocityCommand.java

@@ -29,7 +29,7 @@ public class VelocityCommand implements Command {
                 .append(TextComponent.of(" or the ").resetStyle())
                 .append(TextComponent.builder("Velocity GitHub")
                         .color(TextColor.GREEN)
-                        .clickEvent(new ClickEvent(ClickEvent.Action.OPEN_URL, "https://github.com/astei/velocity"))
+                        .clickEvent(new ClickEvent(ClickEvent.Action.OPEN_URL, "https://github.com/VelocityPowered/Velocity"))
                         .build())
                 .build();
 

proxy/src/main/java/com/velocitypowered/proxy/config/VelocityConfiguration.java

@@ -1,5 +1,6 @@
 package com.velocitypowered.proxy.config;
 
+import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableMap;
 import com.moandjiezana.toml.Toml;
 import com.velocitypowered.api.util.Favicon;
@@ -48,7 +49,7 @@ public class VelocityConfiguration extends AnnotatedConfig {
     @Comment({
         "Should we forward IP addresses and other data to backend servers?",
         "Available options:",
-        "- \"none\":   No forwarding will be done. All players will appear to be Should we forward IP addresses and other data to backend servers?connecting from the proxy",
+        "- \"none\":   No forwarding will be done. All players will appear to be connecting from the proxy",
         "            and will have offline-mode UUIDs.",
         "- \"legacy\": Forward player IPs and UUIDs in BungeeCord-compatible fashion. Use this if you run",
         "            servers using Minecraft 1.12 or lower.",
@@ -62,6 +63,10 @@ public class VelocityConfiguration extends AnnotatedConfig {
     @ConfigKey("forwarding-secret")
     private byte[] forwardingSecret = generateRandomString(12).getBytes(StandardCharsets.UTF_8);
 
+    @Comment("Announce whether or not your server supports Forge/FML. If you run a modded server, we suggest turning this on.")
+    @ConfigKey("announce-forge")
+    private boolean announceForge = false;
+
     @Table("[servers]")
     private final Servers servers;
 
@@ -83,12 +88,13 @@ public class VelocityConfiguration extends AnnotatedConfig {
     }
 
     private VelocityConfiguration(String bind, String motd, int showMaxPlayers, boolean onlineMode,
-            PlayerInfoForwarding playerInfoForwardingMode, byte[] forwardingSecret, Servers servers,
-            Advanced advanced, Query query) {
+            boolean announceForge, PlayerInfoForwarding playerInfoForwardingMode, byte[] forwardingSecret,
+            Servers servers, Advanced advanced, Query query) {
         this.bind = bind;
         this.motd = motd;
         this.showMaxPlayers = showMaxPlayers;
         this.onlineMode = onlineMode;
+        this.announceForge = announceForge;
         this.playerInfoForwardingMode = playerInfoForwardingMode;
         this.forwardingSecret = forwardingSecret;
         this.servers = servers;
@@ -103,13 +109,13 @@ public class VelocityConfiguration extends AnnotatedConfig {
         if (bind.isEmpty()) {
             logger.error("'bind' option is empty.");
             valid = false;
-        }
-
-        try {
-            AddressUtil.parseAddress(bind);
-        } catch (IllegalArgumentException e) {
-            logger.error("'bind' option does not specify a valid IP address.", e);
-            valid = false;
+        } else {
+            try {
+                AddressUtil.parseAddress(bind);
+            } catch (IllegalArgumentException e) {
+                logger.error("'bind' option does not specify a valid IP address.", e);
+                valid = false;
+            }
         }
 
         if (!onlineMode) {
@@ -118,11 +124,11 @@ public class VelocityConfiguration extends AnnotatedConfig {
 
         switch (playerInfoForwardingMode) {
             case NONE:
-                logger.info("Player info forwarding is disabled! All players will appear to be connecting from the proxy and will have offline-mode UUIDs.");
+                logger.warn("Player info forwarding is disabled! All players will appear to be connecting from the proxy and will have offline-mode UUIDs.");
                 break;
             case MODERN:
-                if (forwardingSecret.length == 0) {
-                    logger.error("You don't have a forwarding secret set.");
+                if (forwardingSecret == null || forwardingSecret.length == 0) {
+                    logger.error("You don't have a forwarding secret set. This is required for security.");
                     valid = false;
                 }
                 break;
@@ -148,7 +154,7 @@ public class VelocityConfiguration extends AnnotatedConfig {
 
             for (String s : servers.getAttemptConnectionOrder()) {
                 if (!servers.getServers().containsKey(s)) {
-                    logger.error("Fallback server " + s + " doesn't exist!");
+                    logger.error("Fallback server " + s + " is not registered in your configuration!");
                     valid = false;
                 }
             }
@@ -165,18 +171,18 @@ public class VelocityConfiguration extends AnnotatedConfig {
             logger.error("Invalid compression level {}", advanced.compressionLevel);
             valid = false;
         } else if (advanced.compressionLevel == 0) {
-            logger.warn("ALL packets going through the proxy are going to be uncompressed. This will increase bandwidth usage.");
+            logger.warn("ALL packets going through the proxy will be uncompressed. This will increase bandwidth usage.");
         }
 
         if (advanced.compressionThreshold < -1) {
             logger.error("Invalid compression threshold {}", advanced.compressionLevel);
             valid = false;
         } else if (advanced.compressionThreshold == 0) {
-            logger.warn("ALL packets going through the proxy are going to be compressed. This may hurt performance.");
+            logger.warn("ALL packets going through the proxy will be compressed. This will compromise throughput and increase CPU usage!");
         }
 
         if (advanced.loginRatelimit < 0) {
-            logger.error("Invalid login ratelimit {}", advanced.loginRatelimit);
+            logger.error("Invalid login ratelimit {}ms", advanced.loginRatelimit);
             valid = false;
         }
 
@@ -217,7 +223,7 @@ public class VelocityConfiguration extends AnnotatedConfig {
             if (motd.startsWith("{")) {
                 motdAsComponent = ComponentSerializers.JSON.deserialize(motd);
             } else {
-                motdAsComponent = ComponentSerializers.LEGACY.deserialize(LegacyChatColorUtils.translate('&', motd));
+                motdAsComponent = ComponentSerializers.LEGACY.deserialize(motd, '&');
             }
         }
         return motdAsComponent;
@@ -263,54 +269,34 @@ public class VelocityConfiguration extends AnnotatedConfig {
         return favicon;
     }
 
-    private void setBind(String bind) {
-        this.bind = bind;
+    public boolean isAnnounceForge() {
+        return announceForge;
     }
 
-    private void setMotd(String motd) {
-        this.motd = motd;
+    public int getConnectTimeout() {
+        return advanced.getConnectionTimeout();
     }
 
-    private void setShowMaxPlayers(int showMaxPlayers) {
-        this.showMaxPlayers = showMaxPlayers;
-    }
-
-    private void setOnlineMode(boolean onlineMode) {
-        this.onlineMode = onlineMode;
-    }
-
-    private void setPlayerInfoForwardingMode(PlayerInfoForwarding playerInfoForwardingMode) {
-        this.playerInfoForwardingMode = playerInfoForwardingMode;
-    }
-
-    private void setForwardingSecret(byte[] forwardingSecret) {
-        this.forwardingSecret = forwardingSecret;
-    }
-
-    private void setMotdAsComponent(Component motdAsComponent) {
-        this.motdAsComponent = motdAsComponent;
-    }
-
-    private void setFavicon(Favicon favicon) {
-        this.favicon = favicon;
+    public int getReadTimeout() {
+        return advanced.getReadTimeout();
     }
 
     @Override
     public String toString() {
-
-        return "VelocityConfiguration{"
-                + "bind='" + bind + '\''
-                + ", motd='" + motd + '\''
-                + ", showMaxPlayers=" + showMaxPlayers
-                + ", onlineMode=" + onlineMode
-                + ", playerInfoForwardingMode=" + playerInfoForwardingMode
-                + ", forwardingSecret=" + ByteBufUtil.hexDump(forwardingSecret)
-                + ", servers=" + servers
-                + ", advanced=" + advanced
-                + ", query=" + query
-                + ", motdAsComponent=" + motdAsComponent
-                + ", favicon=" + favicon
-                + '}';
+        return MoreObjects.toStringHelper(this)
+                .add("configVersion", configVersion)
+                .add("bind", bind)
+                .add("motd", motd)
+                .add("showMaxPlayers", showMaxPlayers)
+                .add("onlineMode", onlineMode)
+                .add("playerInfoForwardingMode", playerInfoForwardingMode)
+                .add("forwardingSecret", forwardingSecret)
+                .add("announceForge", announceForge)
+                .add("servers", servers)
+                .add("advanced", advanced)
+                .add("query", query)
+                .add("favicon", favicon)
+                .toString();
     }
 
     public static VelocityConfiguration read(Path path) throws IOException {
@@ -335,6 +321,7 @@ public class VelocityConfiguration extends AnnotatedConfig {
                 toml.getString("motd", "&3A Velocity Server"),
                 toml.getLong("show-max-players", 500L).intValue(),
                 toml.getBoolean("online-mode", true),
+                toml.getBoolean("announce-forge", false),
                 PlayerInfoForwarding.valueOf(toml.getString("player-info-forwarding-mode", "MODERN").toUpperCase()),
                 forwardingSecret,
                 servers,
@@ -441,21 +428,23 @@ public class VelocityConfiguration extends AnnotatedConfig {
             "Disable by setting to 0"})
         @ConfigKey("login-ratelimit")
         private int loginRatelimit = 3000;
+        @Comment({"Specify a custom timeout for connection timeouts here. The default is five seconds."})
+        @ConfigKey("connection-timeout")
+        private int connectionTimeout = 5000;
+        @Comment({"Specify a read timeout for connections here. The default is 30 seconds."})
+        @ConfigKey("read-timeout")
+        private int readTimeout = 30000;
 
         private Advanced() {
         }
 
-        private Advanced(int compressionThreshold, int compressionLevel, int loginRatelimit) {
-            this.compressionThreshold = compressionThreshold;
-            this.compressionLevel = compressionLevel;
-            this.loginRatelimit = loginRatelimit;
-        }
-
         private Advanced(Toml toml) {
             if (toml != null) {
                 this.compressionThreshold = toml.getLong("compression-threshold", 1024L).intValue();
                 this.compressionLevel = toml.getLong("compression-level", -1L).intValue();
                 this.loginRatelimit = toml.getLong("login-ratelimit", 3000L).intValue();
+                this.connectionTimeout = toml.getLong("connection-timeout", 5000L).intValue();
+                this.readTimeout = toml.getLong("read-timeout", 30000L).intValue();
             }
         }
 
@@ -463,33 +452,31 @@ public class VelocityConfiguration extends AnnotatedConfig {
             return compressionThreshold;
         }
 
-        public void setCompressionThreshold(int compressionThreshold) {
-            this.compressionThreshold = compressionThreshold;
-        }
-
         public int getCompressionLevel() {
             return compressionLevel;
         }
 
-        public void setCompressionLevel(int compressionLevel) {
-            this.compressionLevel = compressionLevel;
-        }
-
         public int getLoginRatelimit() {
             return loginRatelimit;
         }
 
-        public void setLoginRatelimit(int loginRatelimit) {
-            this.loginRatelimit = loginRatelimit;
+        public int getConnectionTimeout() {
+            return connectionTimeout;
+        }
+
+        public int getReadTimeout() {
+            return readTimeout;
         }
 
         @Override
         public String toString() {
-            return "Advanced{"
-                    + "compressionThreshold=" + compressionThreshold
-                    + ", compressionLevel=" + compressionLevel
-                    + ", loginRatelimit=" + loginRatelimit
-                    + '}';
+            return "Advanced{" +
+                    "compressionThreshold=" + compressionThreshold +
+                    ", compressionLevel=" + compressionLevel +
+                    ", loginRatelimit=" + loginRatelimit +
+                    ", connectionTimeout=" + connectionTimeout +
+                    ", readTimeout=" + readTimeout +
+                    '}';
         }
     }
 
@@ -521,18 +508,10 @@ public class VelocityConfiguration extends AnnotatedConfig {
             return queryEnabled;
         }
 
-        public void setQueryEnabled(boolean queryEnabled) {
-            this.queryEnabled = queryEnabled;
-        }
-
         public int getQueryPort() {
             return queryPort;
         }
 
-        public void setQueryPort(int queryPort) {
-            this.queryPort = queryPort;
-        }
-
         @Override
         public String toString() {
             return "Query{"

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -45,7 +45,9 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     private MinecraftSessionHandler sessionHandler;
     private int protocolVersion;
     private MinecraftConnectionAssociation association;
+    private boolean isLegacyForge;
     private final VelocityServer server;
+    private boolean canSendLegacyFMLResetPacket = false;
 
     public MinecraftConnection(Channel channel, VelocityServer server) {
         this.channel = channel;
@@ -105,6 +107,13 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
         }
     }
 
+    @Override
+    public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
+        if (sessionHandler != null) {
+            sessionHandler.writabilityChanged();
+        }
+    }
+
     public void write(Object msg) {
         if (channel.isActive()) {
             channel.writeAndFlush(msg, channel.voidPromise());
@@ -222,4 +231,20 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     public void setAssociation(MinecraftConnectionAssociation association) {
         this.association = association;
     }
+
+    public boolean isLegacyForge() {
+        return isLegacyForge;
+    }
+
+    public void setLegacyForge(boolean isForge) {
+        this.isLegacyForge = isForge;
+    }
+
+    public boolean canSendLegacyFMLResetPacket() {
+        return canSendLegacyFMLResetPacket;
+    }
+
+    public void setCanSendLegacyFMLResetPacket(boolean canSendLegacyFMLResetPacket) {
+        this.canSendLegacyFMLResetPacket = isLegacyForge && canSendLegacyFMLResetPacket;
+    }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftSessionHandler.java

@@ -29,4 +29,8 @@ public interface MinecraftSessionHandler {
     default void exception(Throwable throwable) {
 
     }
+
+    default void writabilityChanged() {
+
+    }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/VelocityConstants.java

@@ -6,4 +6,10 @@ public class VelocityConstants {
     }
 
     public static final String VELOCITY_IP_FORWARDING_CHANNEL = "velocity:player_info";
+
+    public static final String FORGE_LEGACY_HANDSHAKE_CHANNEL = "FML|HS";
+    public static final String FORGE_LEGACY_CHANNEL = "FML";
+    public static final String FORGE_MULTIPART_LEGACY_CHANNEL = "FML|MP";
+
+    public static final byte[] FORGE_LEGACY_HANDSHAKE_RESET_DATA = new byte[] { -2, 0 };
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -3,7 +3,9 @@ package com.velocitypowered.proxy.connection.backend;
 import com.velocitypowered.api.event.connection.PluginMessageEvent;
 import com.velocitypowered.api.event.player.ServerConnectedEvent;
 import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.VelocityConstants;
 import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
+import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolConstants;
 import com.velocitypowered.proxy.protocol.packet.*;
@@ -30,7 +32,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
         if (!connection.getPlayer().isActive()) {
             // Connection was left open accidentally. Close it so as to avoid "You logged in from another location"
             // errors.
-            connection.getMinecraftConnection().close();
+            connection.disconnect();
             return;
         }
 
@@ -42,6 +44,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
             connection.getPlayer().getConnection().write(packet);
         } else if (packet instanceof Disconnect) {
             Disconnect original = (Disconnect) packet;
+            connection.disconnect();
             connection.getPlayer().handleConnectionException(connection.getServerInfo(), original);
         } else if (packet instanceof JoinGame) {
             playerHandler.handleBackendJoinGame((JoinGame) packet);
@@ -67,6 +70,20 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
                 return;
             }
 
+            if (!connection.hasCompletedJoin() && pm.getChannel().equals(VelocityConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
+                if (!connection.isLegacyForge()) {
+                    connection.setLegacyForge(true);
+
+                    // We must always reset the handshake before a modded connection is established if
+                    // we haven't done so already.
+                    connection.getPlayer().sendLegacyForgeHandshakeResetPacket();
+                }
+
+                // Always forward these messages during login
+                connection.getPlayer().getConnection().write(pm);
+                return;
+            }
+
             PluginMessageEvent event = new PluginMessageEvent(connection, connection.getPlayer(), server.getChannelRegistrar().getFromId(pm.getChannel()),
                     pm.getData());
             server.getEventManager().fire(event)
@@ -86,10 +103,13 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
         if (!connection.getPlayer().isActive()) {
             // Connection was left open accidentally. Close it so as to avoid "You logged in from another location"
             // errors.
-            connection.getMinecraftConnection().close();
+            connection.disconnect();
             return;
         }
-        connection.getPlayer().getConnection().write(buf.retain());
+
+        if (connection.hasCompletedJoin()) {
+            connection.getPlayer().getConnection().write(buf.retain());
+        }
     }
 
     @Override
@@ -97,16 +117,29 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
         connection.getPlayer().handleConnectionException(connection.getServerInfo(), throwable);
     }
 
+    public VelocityServer getServer() {
+        return server;
+    }
+
+    @Override
+    public void disconnected() {
+        if (connection.isGracefulDisconnect()) {
+            return;
+        }
+        connection.getPlayer().handleConnectionException(connection.getServerInfo(), Disconnect.create(ConnectionMessages.UNEXPECTED_DISCONNECT));
+    }
+
     private boolean canForwardPluginMessage(PluginMessage message) {
         ClientPlaySessionHandler playerHandler =
                 (ClientPlaySessionHandler) connection.getPlayer().getConnection().getSessionHandler();
-        boolean isMCMessage;
+        boolean isMCOrFMLMessage;
         if (connection.getMinecraftConnection().getProtocolVersion() <= ProtocolConstants.MINECRAFT_1_12_2) {
-            isMCMessage = message.getChannel().startsWith("MC|");
+            String channel = message.getChannel();
+            isMCOrFMLMessage = channel.startsWith("MC|") || channel.startsWith(VelocityConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL);
         } else {
-            isMCMessage = message.getChannel().startsWith("minecraft:");
+            isMCOrFMLMessage = message.getChannel().startsWith("minecraft:");
         }
-        return isMCMessage || playerHandler.getClientPluginMsgChannels().contains(message.getChannel()) ||
+        return isMCOrFMLMessage || playerHandler.getClientPluginMsgChannels().contains(message.getChannel()) ||
                 server.getChannelRegistrar().registered(message.getChannel());
     }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/LoginSessionHandler.java

@@ -84,6 +84,10 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
                 connection.getPlayer().getConnection().setSessionHandler(new ClientPlaySessionHandler(server, connection.getPlayer()));
             } else {
                 // The previous server connection should become obsolete.
+                // Before we remove it, if the server we are departing is modded, we must always reset the client state.
+                if (existingConnection.isLegacyForge()) {
+                    connection.getPlayer().sendLegacyForgeHandshakeResetPacket();
+                }
                 existingConnection.disconnect();
             }
 
@@ -119,7 +123,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
         }
     }
 
-    static ByteBuf createForwardingData(byte[] hmacSecret, String address, GameProfile profile) {
+    private static ByteBuf createForwardingData(byte[] hmacSecret, String address, GameProfile profile) {
         ByteBuf dataToForward = Unpooled.buffer();
         ByteBuf finalData = Unpooled.buffer();
         try {

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -33,7 +33,6 @@ import static com.velocitypowered.proxy.network.Connections.HANDLER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_DECODER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.READ_TIMEOUT;
-import static com.velocitypowered.proxy.network.Connections.SERVER_READ_TIMEOUT_SECONDS;
 
 public class VelocityServerConnection implements MinecraftConnectionAssociation, ServerConnection {
     static final AttributeKey<CompletableFuture<ConnectionRequestBuilder.Result>> CONNECTION_NOTIFIER =
@@ -43,6 +42,9 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     private final ConnectedPlayer proxyPlayer;
     private final VelocityServer server;
     private MinecraftConnection minecraftConnection;
+    private boolean legacyForge = false;
+    private boolean hasCompletedJoin = false;
+    private boolean gracefulDisconnect = false;
 
     public VelocityServerConnection(ServerInfo target, ConnectedPlayer proxyPlayer, VelocityServer server) {
         this.serverInfo = target;
@@ -57,7 +59,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
                     @Override
                     protected void initChannel(Channel ch) throws Exception {
                         ch.pipeline()
-                                .addLast(READ_TIMEOUT, new ReadTimeoutHandler(SERVER_READ_TIMEOUT_SECONDS, TimeUnit.SECONDS))
+                                .addLast(READ_TIMEOUT, new ReadTimeoutHandler(server.getConfiguration().getReadTimeout(), TimeUnit.SECONDS))
                                 .addLast(FRAME_DECODER, new MinecraftVarintFrameDecoder())
                                 .addLast(FRAME_ENCODER, MinecraftVarintLengthEncoder.INSTANCE)
                                 .addLast(MINECRAFT_DECODER, new MinecraftDecoder(ProtocolConstants.Direction.CLIENTBOUND))
@@ -107,6 +109,8 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
         handshake.setProtocolVersion(proxyPlayer.getConnection().getProtocolVersion());
         if (forwardingMode == PlayerInfoForwarding.LEGACY) {
             handshake.setServerAddress(createBungeeForwardingAddress());
+        } else if (proxyPlayer.getConnection().isLegacyForge()) {
+            handshake.setServerAddress(handshake.getServerAddress() + "\0FML\0");
         } else {
             handshake.setServerAddress(serverInfo.getAddress().getHostString());
         }
@@ -122,6 +126,12 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
         minecraftConnection.write(login);
     }
 
+    public void writeIfJoined(PluginMessage message) {
+        if (hasCompletedJoin) {
+            minecraftConnection.write(message);
+        }
+    }
+
     public MinecraftConnection getMinecraftConnection() {
         return minecraftConnection;
     }
@@ -136,8 +146,11 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     }
 
     public void disconnect() {
-        minecraftConnection.close();
-        minecraftConnection = null;
+        if (minecraftConnection != null) {
+            minecraftConnection.close();
+            minecraftConnection = null;
+            gracefulDisconnect = true;
+        }
     }
 
     @Override
@@ -154,4 +167,24 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
         message.setData(data);
         minecraftConnection.write(message);
     }
+
+    public boolean isLegacyForge() {
+        return legacyForge;
+    }
+
+    public void setLegacyForge(boolean modded) {
+        legacyForge = modded;
+    }
+
+    public boolean hasCompletedJoin() {
+        return hasCompletedJoin;
+    }
+
+    public void setHasCompletedJoin(boolean hasCompletedJoin) {
+        this.hasCompletedJoin = hasCompletedJoin;
+    }
+
+    public boolean isGracefulDisconnect() {
+        return gracefulDisconnect;
+    }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -3,6 +3,8 @@ package com.velocitypowered.proxy.connection.client;
 import com.velocitypowered.api.event.connection.DisconnectEvent;
 import com.velocitypowered.api.event.connection.PluginMessageEvent;
 import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.VelocityConstants;
+import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolConstants;
 import com.velocitypowered.proxy.protocol.packet.*;
@@ -23,7 +25,7 @@ import java.util.*;
  */
 public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     private static final Logger logger = LogManager.getLogger(ClientPlaySessionHandler.class);
-    private static final int MAX_PLUGIN_CHANNELS = 128;
+    private static final int MAX_PLUGIN_CHANNELS = 1024;
 
     private final ConnectedPlayer player;
     private long lastPingID = -1;
@@ -31,6 +33,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     private boolean spawned = false;
     private final List<UUID> serverBossBars = new ArrayList<>();
     private final Set<String> clientPluginMsgChannels = new HashSet<>();
+    private final Queue<PluginMessage> loginPluginMessages = new ArrayDeque<>();
     private final VelocityServer server;
 
     public ClientPlaySessionHandler(VelocityServer server, ConnectedPlayer player) {
@@ -51,6 +54,12 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handle(MinecraftPacket packet) {
+        VelocityServerConnection serverConnection = player.getConnectedServer();
+        if (serverConnection == null) {
+            // No server connection yet, probably transitioning.
+            return;
+        }
+
         if (packet instanceof KeepAlive) {
             KeepAlive keepAlive = (KeepAlive) packet;
             if (keepAlive.getRandomId() != lastPingID) {
@@ -60,6 +69,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             }
             player.setPing(System.currentTimeMillis() - lastPingSent);
             resetPingData();
+            serverConnection.getMinecraftConnection().write(packet);
+            return;
         }
 
         if (packet instanceof ClientSettings) {
@@ -106,7 +117,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
                         player.getConnection().write(response);
                     } else {
-                        player.getConnectedServer().getMinecraftConnection().write(packet);
+                        serverConnection.getMinecraftConnection().write(packet);
                     }
                 } catch (Exception e) {
                     logger.error("Unable to provide tab list completions for " + player.getUsername() + " for command '" + req.getCommand() + "'", e);
@@ -121,12 +132,22 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         }
 
         // If we don't want to handle this packet, just forward it on.
-        player.getConnectedServer().getMinecraftConnection().write(packet);
+        if (serverConnection.hasCompletedJoin()) {
+            serverConnection.getMinecraftConnection().write(packet);
+        }
     }
 
     @Override
     public void handleUnknown(ByteBuf buf) {
-        player.getConnectedServer().getMinecraftConnection().write(buf.retain());
+        VelocityServerConnection serverConnection = player.getConnectedServer();
+        if (serverConnection == null) {
+            // No server connection yet, probably transitioning.
+            return;
+        }
+
+        if (serverConnection.hasCompletedJoin()) {
+            serverConnection.getMinecraftConnection().write(buf.retain());
+        }
     }
 
     @Override
@@ -144,12 +165,31 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
                 .build());
     }
 
+    @Override
+    public void writabilityChanged() {
+        VelocityServerConnection server = player.getConnectedServer();
+        if (server != null) {
+            boolean writable = player.getConnection().getChannel().isWritable();
+            server.getMinecraftConnection().getChannel().config().setAutoRead(writable);
+        }
+    }
+
     public void handleBackendJoinGame(JoinGame joinGame) {
-        resetPingData(); // reset ping data;
+        resetPingData(); // reset ping data
         if (!spawned) {
-            // nothing special to do here
+            // Nothing special to do with regards to spawning the player
             spawned = true;
             player.getConnection().delayedWrite(joinGame);
+
+            // We have something special to do for legacy Forge servers - during first connection the FML handshake
+            // will transition to complete regardless. Thus, we need to ensure that a reset packet is ALWAYS sent on
+            // first switch.
+            //
+            // As we know that calling this branch only happens on first join, we set that if we are a Forge
+            // client that we must reset on the next switch.
+            //
+            // The call will handle if the player is not a Forge player appropriately.
+            player.getConnection().setCanSendLegacyFMLResetPacket(true);
         } else {
             // Ah, this is the meat and potatoes of the whole venture!
             //
@@ -193,17 +233,38 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
                     channel, toRegister));
         }
 
+        // If we had plugin messages queued during login/FML handshake, send them now.
+        PluginMessage pm;
+        while ((pm = loginPluginMessages.poll()) != null) {
+            player.getConnectedServer().getMinecraftConnection().delayedWrite(pm);
+        }
+
         // Flush everything
         player.getConnection().flush();
         player.getConnectedServer().getMinecraftConnection().flush();
+        player.getConnectedServer().setHasCompletedJoin(true);
+        if (player.getConnectedServer().isLegacyForge()) {
+            // We only need to indicate we can send a reset packet if we complete a handshake, that is,
+            // logged onto a Forge server.
+            //
+            // The special case is if we log onto a Vanilla server as our first server, FML will treat this
+            // as complete and **will** need a reset packet sending at some point. We will handle this
+            // during initial player connection if the player is detected to be forge.
+            //
+            // This is why we use an if statement rather than the result of VelocityServerConnection#isLegacyForge()
+            // because we don't want to set it false if this is a first connection to a Vanilla server.
+            //
+            // See LoginSessionHandler#handle for where the counterpart to this method is
+            player.getConnection().setCanSendLegacyFMLResetPacket(true);
+        }
     }
 
     public List<UUID> getServerBossBars() {
         return serverBossBars;
     }
 
-    public void handleClientPluginMessage(PluginMessage packet) {
-        if (packet.getChannel().equals("REGISTER") || packet.getChannel().equals("minecraft:register")) {
+    private void handleClientPluginMessage(PluginMessage packet) {
+        if (PluginMessageUtil.isMCRegister(packet)) {
             List<String> actuallyRegistered = new ArrayList<>();
             List<String> channels = PluginMessageUtil.getChannels(packet);
             for (String channel : channels) {
@@ -220,28 +281,32 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
                 PluginMessage newRegisterPacket = PluginMessageUtil.constructChannelsPacket(packet.getChannel(), actuallyRegistered);
                 player.getConnectedServer().getMinecraftConnection().write(newRegisterPacket);
             }
-
-            return;
-        }
-
-        if (packet.getChannel().equals("UNREGISTER") || packet.getChannel().equals("minecraft:unregister")) {
+        } else if (PluginMessageUtil.isMCUnregister(packet)) {
             List<String> channels = PluginMessageUtil.getChannels(packet);
             clientPluginMsgChannels.removeAll(channels);
-        }
-
-        if (PluginMessageUtil.isMCBrand(packet)) {
+            player.getConnectedServer().getMinecraftConnection().write(packet);
+        } else if (PluginMessageUtil.isMCBrand(packet)) {
             player.getConnectedServer().getMinecraftConnection().write(PluginMessageUtil.rewriteMCBrand(packet));
-            return;
+        } else if (player.getConnectedServer().isLegacyForge() && !player.getConnectedServer().hasCompletedJoin()) {
+            if (packet.getChannel().equals(VelocityConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL)) {
+                // Always forward the FML handshake to the remote server.
+                player.getConnectedServer().getMinecraftConnection().write(packet);
+            } else {
+                // The client is trying to send messages too early. This is primarily caused by mods, but it's further
+                // aggravated by Velocity. To work around these issues, we will queue any non-FML handshake messages to
+                // be sent once the JoinGame packet has been received by the proxy.
+                loginPluginMessages.add(packet);
+            }
+        } else {
+            PluginMessageEvent event = new PluginMessageEvent(player, player.getConnectedServer(),
+                    server.getChannelRegistrar().getFromId(packet.getChannel()), packet.getData());
+            server.getEventManager().fire(event)
+                    .thenAcceptAsync(pme -> {
+                        if (pme.getResult().isAllowed()) {
+                            player.getConnectedServer().getMinecraftConnection().write(packet);
+                        }
+                    }, player.getConnectedServer().getMinecraftConnection().getChannel().eventLoop());
         }
-
-        PluginMessageEvent event = new PluginMessageEvent(player, player.getConnectedServer(),
-                server.getChannelRegistrar().getFromId(packet.getChannel()), packet.getData());
-        server.getEventManager().fire(event)
-                .thenAcceptAsync(pme -> {
-                    if (pme.getResult().isAllowed()) {
-                        player.getConnectedServer().getMinecraftConnection().write(packet);
-                    }
-                }, player.getConnectedServer().getMinecraftConnection().getChannel().eventLoop());
     }
 
     public Set<String> getClientPluginMsgChannels() {

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientSettingsWrapper.java

@@ -12,7 +12,7 @@ public class ClientSettingsWrapper implements PlayerSettings {
     private final SkinParts parts;
     private Locale locale = null;
 
-    public ClientSettingsWrapper(ClientSettings settings) {
+    ClientSettingsWrapper(ClientSettings settings) {
         this.settings = settings;
         this.parts = new SkinParts((byte) settings.getSkinParts());
     }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -2,6 +2,7 @@ package com.velocitypowered.proxy.connection.client;
 
 import com.google.common.base.Preconditions;
 import com.google.gson.JsonObject;
+import com.velocitypowered.api.event.player.KickedFromServerEvent;
 import com.velocitypowered.api.event.player.PlayerSettingsChangedEvent;
 import com.velocitypowered.api.event.player.ServerPreConnectEvent;
 import com.velocitypowered.api.permission.PermissionFunction;
@@ -14,6 +15,7 @@ import com.velocitypowered.api.util.MessagePosition;
 import com.velocitypowered.api.proxy.Player;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnectionAssociation;
+import com.velocitypowered.proxy.connection.VelocityConstants;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
 import com.velocitypowered.api.util.GameProfile;
@@ -36,6 +38,7 @@ import net.kyori.text.serializer.PlainComponentSerializer;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.net.InetSocketAddress;
 import java.util.List;
@@ -190,7 +193,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
             logger.error("{}: unable to connect to server {}", this, info.getName(), throwable);
             userMessage = "Exception connecting to server " + info.getName();
         }
-        handleConnectionException(info, TextComponent.builder()
+        handleConnectionException(info, null, TextComponent.builder()
                 .content(userMessage + ": ")
                 .color(TextColor.RED)
                 .append(TextComponent.of(error, TextColor.WHITE))
@@ -202,17 +205,23 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         String plainTextReason = PASS_THRU_TRANSLATE.serialize(disconnectReason);
         if (connectedServer != null && connectedServer.getServerInfo().equals(info)) {
             logger.error("{}: kicked from server {}: {}", this, info.getName(), plainTextReason);
+            handleConnectionException(info, disconnectReason, TextComponent.builder()
+                    .content("Kicked from " + info.getName() + ": ")
+                    .color(TextColor.RED)
+                    .append(disconnectReason)
+                    .build());
         } else {
             logger.error("{}: disconnected while connecting to {}: {}", this, info.getName(), plainTextReason);
+            handleConnectionException(info, disconnectReason, TextComponent.builder()
+                    .content("Unable to connect to " + info.getName() + ": ")
+                    .color(TextColor.RED)
+                    .append(disconnectReason)
+                    .build());
         }
-        handleConnectionException(info, TextComponent.builder()
-                .content("Unable to connect to " + info.getName() + ": ")
-                .color(TextColor.RED)
-                .append(disconnectReason)
-                .build());
     }
 
-    public void handleConnectionException(ServerInfo info, Component disconnectReason) {
+    private void handleConnectionException(ServerInfo info, @Nullable Component kickReason, Component friendlyReason) {
+        boolean alreadyConnected = connectedServer != null && connectedServer.getServerInfo().equals(info);;
         connectionInFlight = null;
         if (connectedServer == null) {
             // The player isn't yet connected to a server.
@@ -220,14 +229,29 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
             if (nextServer.isPresent()) {
                 createConnectionRequest(nextServer.get()).fireAndForget();
             } else {
-                connection.closeWith(Disconnect.create(disconnectReason));
+                connection.closeWith(Disconnect.create(friendlyReason));
             }
         } else if (connectedServer.getServerInfo().equals(info)) {
             // Already connected to the server being disconnected from.
-            // TODO: ServerKickEvent
-            connection.closeWith(Disconnect.create(disconnectReason));
+            if (kickReason != null) {
+                server.getEventManager().fire(new KickedFromServerEvent(this, info, kickReason, !alreadyConnected, friendlyReason))
+                        .thenAcceptAsync(event -> {
+                            if (event.getResult() instanceof KickedFromServerEvent.DisconnectPlayer) {
+                                KickedFromServerEvent.DisconnectPlayer res = (KickedFromServerEvent.DisconnectPlayer) event.getResult();
+                                connection.closeWith(Disconnect.create(res.getReason()));
+                            } else if (event.getResult() instanceof KickedFromServerEvent.RedirectPlayer) {
+                                KickedFromServerEvent.RedirectPlayer res = (KickedFromServerEvent.RedirectPlayer) event.getResult();
+                                createConnectionRequest(res.getServer()).fireAndForget();
+                            } else {
+                                // In case someone gets creative, assume we want to disconnect the player.
+                                connection.closeWith(Disconnect.create(friendlyReason));
+                            }
+                        }, connection.getChannel().eventLoop());
+            } else {
+                connection.closeWith(Disconnect.create(friendlyReason));
+            }
         } else {
-            connection.write(Chat.create(disconnectReason));
+            connection.write(Chat.create(friendlyReason));
         }
     }
 
@@ -256,7 +280,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         }
 
         // Otherwise, initiate the connection.
-        ServerPreConnectEvent event = new ServerPreConnectEvent(this, ServerPreConnectEvent.ServerResult.allowed(request.getServer()));
+        ServerPreConnectEvent event = new ServerPreConnectEvent(this, request.getServer());
         return server.getEventManager().fire(event)
                 .thenCompose((newEvent) -> {
                     if (!newEvent.getResult().isAllowed()) {
@@ -265,7 +289,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
                         );
                     }
 
-                    return new VelocityServerConnection(newEvent.getResult().getInfo().get(), this, server).connect();
+                    return new VelocityServerConnection(newEvent.getResult().getServer().get(), this, server).connect();
                 });
     }
 
@@ -276,6 +300,16 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         this.connectedServer = serverConnection;
     }
 
+    public void sendLegacyForgeHandshakeResetPacket() {
+        if (connection.canSendLegacyFMLResetPacket()) {
+            PluginMessage resetPacket = new PluginMessage();
+            resetPacket.setChannel(VelocityConstants.FORGE_LEGACY_HANDSHAKE_CHANNEL);
+            resetPacket.setData(VelocityConstants.FORGE_LEGACY_HANDSHAKE_RESET_DATA);
+            connection.write(resetPacket);
+            connection.setCanSendLegacyFMLResetPacket(false);
+        }
+    }
+
     public void close(TextComponent reason) {
         connection.closeWith(Disconnect.create(reason));
     }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/HandshakeSessionHandler.java

@@ -70,9 +70,12 @@ public class HandshakeSessionHandler implements MinecraftSessionHandler {
                     return;
                 }
 
-                // Make sure legacy forwarding is not in use on this connection. Make sure that we do _not_ reject Forge,
-                // although Velocity does not yet support Forge.
-                if (handshake.getServerAddress().contains("\0") && !handshake.getServerAddress().endsWith("\0FML\0")) {
+                // Determine if we're using Forge (1.8 to 1.12, may not be the case in 1.13) and store that in the connection
+                boolean isForge = handshake.getServerAddress().endsWith("\0FML\0");
+                connection.setLegacyForge(isForge);
+
+                // Make sure legacy forwarding is not in use on this connection. Make sure that we do _not_ reject Forge
+                if (handshake.getServerAddress().contains("\0") && !isForge) {
                     connection.closeWith(Disconnect.create(TextComponent.of("Running Velocity behind Velocity is unsupported.")));
                     return;
                 }
@@ -105,6 +108,7 @@ public class HandshakeSessionHandler implements MinecraftSessionHandler {
                     new ServerPing.Version(ProtocolConstants.MAXIMUM_GENERIC_VERSION, "Velocity " + ProtocolConstants.SUPPORTED_GENERIC_VERSION_STRING),
                     new ServerPing.Players(server.getPlayerCount(), configuration.getShowMaxPlayers(), ImmutableList.of()),
                     configuration.getMotdComponent(),
+                    null,
                     null
             );
             ProxyPingEvent event = new ProxyPingEvent(new LegacyInboundConnection(connection), ping);

proxy/src/main/java/com/velocitypowered/proxy/connection/client/LoginSessionHandler.java

@@ -2,12 +2,14 @@ package com.velocitypowered.proxy.connection.client;
 
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.event.connection.LoginEvent;
+import com.velocitypowered.api.event.connection.PostLoginEvent;
 import com.velocitypowered.api.event.connection.PreLoginEvent;
 import com.velocitypowered.api.event.connection.PreLoginEvent.PreLoginComponentResult;
 import com.velocitypowered.api.event.permission.PermissionsSetupEvent;
 import com.velocitypowered.api.event.player.GameProfileRequestEvent;
 import com.velocitypowered.api.proxy.InboundConnection;
 import com.velocitypowered.api.proxy.server.ServerInfo;
+import com.velocitypowered.proxy.config.PlayerInfoForwarding;
 import com.velocitypowered.proxy.connection.VelocityConstants;
 import com.velocitypowered.api.util.GameProfile;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
@@ -31,11 +33,14 @@ import java.net.MalformedURLException;
 import java.net.URL;
 import java.security.GeneralSecurityException;
 import java.security.KeyPair;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Optional;
 import java.util.concurrent.ThreadLocalRandom;
 
 public class LoginSessionHandler implements MinecraftSessionHandler {
+
     private static final Logger logger = LogManager.getLogger(LoginSessionHandler.class);
     private static final String MOJANG_SERVER_AUTH_URL =
             "https://sessionserver.mojang.com/session/minecraft/hasJoined?username=%s&serverId=%s&ip=%s";
@@ -154,7 +159,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
                         return;
                     }
 
-                    if (server.getConfiguration().isOnlineMode() || result.isOnlineModeAllowed()) {
+                    if (!result.isForceOfflineMode() && (server.getConfiguration().isOnlineMode() || result.isOnlineModeAllowed())) {
                         // Request encryption.
                         EncryptionRequest request = generateRequest();
                         this.verify = Arrays.copyOf(request.getVerifyToken(), 4);
@@ -176,6 +181,12 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
     }
 
     private void initializePlayer(GameProfile profile, boolean onlineMode) {
+        if (inbound.isLegacyForge() && server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.LEGACY) {
+            // We want to add the FML token to the properties
+            List<GameProfile.Property> properties = new ArrayList<>(profile.getProperties());
+            properties.add(new GameProfile.Property("forgeClient", "true", ""));
+            profile = new GameProfile(profile.getId(), profile.getName(), properties);
+        }
         GameProfileRequestEvent profileRequestEvent = new GameProfileRequestEvent(apiInbound, profile, onlineMode);
 
         server.getEventManager().fire(profileRequestEvent).thenCompose(profileEvent -> {
@@ -235,7 +246,9 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
 
         logger.info("{} has connected", player);
         inbound.setSessionHandler(new InitialConnectSessionHandler(player));
-        player.createConnectionRequest(toTry.get()).fireAndForget();
+        server.getEventManager().fire(new PostLoginEvent(player)).thenRun(() -> {
+            player.createConnectionRequest(toTry.get()).fireAndForget();
+        });
     }
 
     @Override

proxy/src/main/java/com/velocitypowered/proxy/connection/client/StatusSessionHandler.java

@@ -48,7 +48,8 @@ public class StatusSessionHandler implements MinecraftSessionHandler {
                 new ServerPing.Version(shownVersion, "Velocity " + ProtocolConstants.SUPPORTED_GENERIC_VERSION_STRING),
                 new ServerPing.Players(server.getPlayerCount(), configuration.getShowMaxPlayers(), ImmutableList.of()),
                 configuration.getMotdComponent(),
-                configuration.getFavicon()
+                configuration.getFavicon(),
+                configuration.isAnnounceForge() ? ServerPing.Modinfo.DEFAULT : null
         );
 
         ProxyPingEvent event = new ProxyPingEvent(inboundWrapper, initialPing);

proxy/src/main/java/com/velocitypowered/proxy/connection/util/ConnectionMessages.java

@@ -7,6 +7,7 @@ public class ConnectionMessages {
     public static final TextComponent ALREADY_CONNECTED = TextComponent.of("You are already connected to this server!", TextColor.RED);
     public static final TextComponent IN_PROGRESS = TextComponent.of("You are already connecting to a server!", TextColor.RED);
     public static final TextComponent INTERNAL_SERVER_CONNECTION_ERROR = TextComponent.of("Internal server connection error");
+    public static final TextComponent UNEXPECTED_DISCONNECT = TextComponent.of("Unexpectedly disconnected from server - crash?");
 
     private ConnectionMessages() {
         throw new AssertionError();

proxy/src/main/java/com/velocitypowered/proxy/network/ConnectionManager.java

@@ -16,11 +16,7 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftVarintFrameDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftVarintLengthEncoder;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelFutureListener;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelOption;
-import io.netty.channel.EventLoopGroup;
+import io.netty.channel.*;
 import io.netty.channel.epoll.Epoll;
 import io.netty.channel.epoll.EpollDatagramChannel;
 import io.netty.channel.epoll.EpollEventLoopGroup;
@@ -48,6 +44,8 @@ import java.util.concurrent.TimeUnit;
 import static com.velocitypowered.proxy.network.Connections.*;
 
 public final class ConnectionManager {
+    private static final WriteBufferWaterMark SERVER_WRITE_MARK = new WriteBufferWaterMark(1 << 16, 1 << 18);
+
     private static final Logger logger = LogManager.getLogger(ConnectionManager.class);
 
     private final Set<Channel> endpoints = new HashSet<>();
@@ -72,11 +70,12 @@ public final class ConnectionManager {
         final ServerBootstrap bootstrap = new ServerBootstrap()
                 .channel(this.transportType.serverSocketChannelClass)
                 .group(this.bossGroup, this.workerGroup)
+                .childOption(ChannelOption.WRITE_BUFFER_WATER_MARK, SERVER_WRITE_MARK)
                 .childHandler(new ChannelInitializer<Channel>() {
                     @Override
                     protected void initChannel(final Channel ch) {
                         ch.pipeline()
-                                .addLast(READ_TIMEOUT, new ReadTimeoutHandler(CLIENT_READ_TIMEOUT_SECONDS, TimeUnit.SECONDS))
+                                .addLast(READ_TIMEOUT, new ReadTimeoutHandler(server.getConfiguration().getReadTimeout(), TimeUnit.SECONDS))
                                 .addLast(LEGACY_PING_DECODER, new LegacyPingDecoder())
                                 .addLast(FRAME_DECODER, new MinecraftVarintFrameDecoder())
                                 .addLast(LEGACY_PING_ENCODER, LegacyPingEncoder.INSTANCE)
@@ -126,7 +125,9 @@ public final class ConnectionManager {
     public Bootstrap createWorker() {
         return new Bootstrap()
                 .channel(this.transportType.socketChannelClass)
-                .group(this.workerGroup);
+                .group(this.workerGroup)
+                .option(ChannelOption.TCP_NODELAY, true)
+                .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, server.getConfiguration().getConnectTimeout());
     }
 
     public void shutdown() {

proxy/src/main/java/com/velocitypowered/proxy/network/Connections.java

@@ -13,7 +13,4 @@ public interface Connections {
     String MINECRAFT_DECODER = "minecraft-decoder";
     String MINECRAFT_ENCODER = "minecraft-encoder";
     String READ_TIMEOUT = "read-timeout";
-
-    int CLIENT_READ_TIMEOUT_SECONDS = 30; // client -> proxy
-    int SERVER_READ_TIMEOUT_SECONDS = 30; // proxy -> server
 }

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -1,5 +1,6 @@
 package com.velocitypowered.proxy.protocol;
 
+import com.google.common.base.Strings;
 import com.google.common.primitives.ImmutableIntArray;
 import com.velocitypowered.proxy.protocol.packet.*;
 import io.netty.util.collection.IntObjectHashMap;
@@ -258,9 +259,18 @@ public enum StateRegistry {
 
             @Override
             public String toString() {
+                StringBuilder mappingAsString = new StringBuilder("{");
+                for (Object2IntMap.Entry<Class<? extends MinecraftPacket>> entry : packetClassToId.object2IntEntrySet()) {
+                    mappingAsString.append(entry.getKey().getSimpleName()).append(" -> ")
+                            .append("0x")
+                            .append(Strings.padStart(Integer.toHexString(entry.getIntValue()), 2, '0'))
+                            .append(", ");
+                }
+                mappingAsString.setLength(mappingAsString.length() - 2);
+                mappingAsString.append("}");
                 return "ProtocolVersion{" +
                         "id=" + id +
-                        ", packetClassToId=" + packetClassToId +
+                        ", packetClassToId=" + mappingAsString.toString() +
                         '}';
             }
         }

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftDecoder.java

@@ -38,11 +38,11 @@ public class MinecraftDecoder extends MessageToMessageDecoder<ByteBuf> {
                 packet.decode(msg, direction, protocolVersion.id);
             } catch (Exception e) {
                 throw new CorruptedFrameException("Error decoding " + packet.getClass() + " Direction " + direction
-                        + " Protocol " + protocolVersion + " State " + state + " ID " + Integer.toHexString(packetId), e);
+                        + " Protocol " + protocolVersion.id + " State " + state + " ID " + Integer.toHexString(packetId), e);
             }
             if (msg.isReadable()) {
                 throw new CorruptedFrameException("Did not read full packet for " + packet.getClass() + " Direction " + direction
-                        + " Protocol " + protocolVersion + " State " + state + " ID " + Integer.toHexString(packetId));
+                        + " Protocol " + protocolVersion.id + " State " + state + " ID " + Integer.toHexString(packetId));
             }
             out.add(packet);
         }

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java

@@ -2,8 +2,10 @@ package com.velocitypowered.proxy.protocol.netty;
 
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.CorruptedFrameException;
 
 import java.util.List;
 
@@ -15,12 +17,31 @@ public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
         }
 
         in.markReaderIndex();
-        int packetLength = ProtocolUtils.readVarInt(in);
-        if (in.readableBytes() < packetLength) {
-            in.resetReaderIndex();
-            return;
+
+        byte[] lenBuf = new byte[3];
+        for (int i = 0; i < lenBuf.length; i++) {
+            if (!in.isReadable()) {
+                in.resetReaderIndex();
+                return;
+            }
+
+            lenBuf[i] = in.readByte();
+            if (lenBuf[i] > 0) {
+                int packetLength = ProtocolUtils.readVarInt(Unpooled.wrappedBuffer(lenBuf));
+                if (packetLength == 0) {
+                    return;
+                }
+
+                if (in.readableBytes() < packetLength) {
+                    in.resetReaderIndex();
+                    return;
+                }
+
+                out.add(in.readRetainedSlice(packetLength));
+                return;
+            }
         }
 
-        out.add(in.readRetainedSlice(packetLength));
+        throw new CorruptedFrameException("VarInt too big");
     }
 }

proxy/src/main/java/com/velocitypowered/proxy/protocol/util/PluginMessageUtil.java

@@ -20,13 +20,20 @@ public enum PluginMessageUtil {
         return message.getChannel().equals("MC|Brand") || message.getChannel().equals("minecraft:brand");
     }
 
+    public static boolean isMCRegister(PluginMessage message) {
+        Preconditions.checkNotNull(message, "message");
+        return message.getChannel().equals("REGISTER") || message.getChannel().equals("minecraft:register");
+    }
+
+    public static boolean isMCUnregister(PluginMessage message) {
+        Preconditions.checkNotNull(message, "message");
+        return message.getChannel().equals("UNREGISTER") || message.getChannel().equals("minecraft:unregister");
+    }
+
     public static List<String> getChannels(PluginMessage message) {
         Preconditions.checkNotNull(message, "message");
-        Preconditions.checkArgument(message.getChannel().equals("REGISTER") ||
-                message.getChannel().equals("UNREGISTER") ||
-                message.getChannel().equals("minecraft:register") ||
-                message.getChannel().equals("minecraft:unregister"),
-                "Unknown channel type " + message.getChannel());
+        Preconditions.checkArgument(isMCRegister(message) || isMCUnregister(message),"Unknown channel type %s",
+                message.getChannel());
         String channels = new String(message.getData(), StandardCharsets.UTF_8);
         return ImmutableList.copyOf(channels.split("\0"));
     }

proxy/src/test/java/com/velocitypowered/proxy/util/concurrency/RecordingThreadFactoryTest.java

@@ -4,6 +4,7 @@ import org.junit.jupiter.api.Test;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -33,4 +34,36 @@ class RecordingThreadFactoryTest {
         Thread.sleep(10);
         assertEquals(0, factory.size());
     }
+
+    @Test
+    void cleanUpAfterExceptionThrown() throws Exception {
+        CountDownLatch started = new CountDownLatch(1);
+        CountDownLatch endThread = new CountDownLatch(1);
+        CountDownLatch hasEnded = new CountDownLatch(1);
+        RecordingThreadFactory factory = new RecordingThreadFactory((ThreadFactory) r -> {
+            Thread t = new Thread(r);
+            t.setUncaughtExceptionHandler((t1, e) -> hasEnded.countDown());
+            return t;
+        });
+        factory.newThread(() -> {
+            started.countDown();
+            assertTrue(factory.currentlyInFactory());
+            assertEquals(1, factory.size());
+            try {
+                endThread.await();
+            } catch (InterruptedException e) {
+                fail(e);
+            }
+            throw new RuntimeException("");
+        }).start();
+        started.await();
+        assertFalse(factory.currentlyInFactory());
+        assertEquals(1, factory.size());
+        endThread.countDown();
+        hasEnded.await();
+
+        // Wait a little bit to ensure the thread got shut down
+        Thread.sleep(10);
+        assertEquals(0, factory.size());
+    }
 }